Printer type element deflection limiter

ABSTRACT

A relatively high-speed rotary serial printer includes a continuously rotating circular disk with a plurality of resilient type carrying finger members flexible in both axial and lateral directions. Each of the finger members has a plastic sleeve element attached thereto such that a predetermined air gap exists between sleeve elements on adjacent finger members. When a print hammer is operated to impact a type element attached at the end of a selected one of the finger members to drive it against a document and effect a character printing upon the document, the deflection of the actuated finger member in the lateral direction is controllably limited by the sleeve element attached thereto butting against the sleeve element on the next or adjacent sleeve element.

[ Oct. 28, 1975 United States Patent 1191 Schacht PRINTER TYPE ELEMENT DEFLECTION 3,805,941 4/1974 Cattaneo............................... 197/53 LIMITER Inventor:

Primary Examiner.]. Reed Fisher (NhlYenter schacht Bmghamton Assistant Examiner-Paul T. Sewell Attorney, Agent, or Firm-Francis V. Giolma [57] ABSTRACT high-speed rotary serial printer includes a s e .m mY a MN S an no lam u BA m, nm .w mm p er m0 .lC e n .W 8 S A M U A relatively continuously rotating circular disk with a plurality of resilient type carrying finger members flexible in both [22] Filed: Nov. 29, 1973 [21] Appl. No.: 420,045

axial and lateral directions. Each of the finger mem- 5 oo. l 3 M 4 1 58 9 3 1 W 9 3 "8 w 1 1 l W 3 m WW9 mw m 0: "Q1," 9 1", u" 1 m" mmmU 1m "0% Us L 1 C s xm UIF 1]] 2 8 555 .1.

References Cited drive it against a document and effect a character UNITED STATES FATE printing upon the document, the deflection of the ac- Reed et al....

tuated finger member in the lateral direction is controllably limited by the sleeve element attached 197/ 18 12 thereto butting against the sleeve element on the next 101/1 1 l or ad acent sleeve element.

101/111 3 Claims, 4 Drawing Figures Wm "t we SS n ee rr rt 00 Tr 3,638,565 2/1972 Drejza et al. 3,724,371 4/1973 Picard.......... 3,747 522 7/1973 l ffli ny PRINTER TYPE ELEMENT DEFLECTION LIMITER CROSS-REFERENCE TO RELATED APPLICATION The improvements to apparatus disclosed in this application includes mechanism disclosed in the application Ser. No. 259,320 filed June 2, 1972 by Johann H. Meier et al and assigned to the same assignee as the present application.

FIELD OF THE INVENTION This invention relates to on-the-fly rotating print disk printers and, more particularly, to the means for controlling the stresses to the type carrying finger members of the disk during a character printing operation.

DESCRIPTION OF PRIOR ART Printing devices comprising a continuously rotating disk having a plurality of flexible type carrying segments and a hammer for causing individual segments to move into contact with a document on a platen are well known in the art. Control means are provided for actuating the hammer at the proper distance relative to the constantly rotating disk so that the preselected character is printed. For example, US. Pat. Nos. 3,442,365; 3,613,856 and 3,651,916, each disclose printing devices of a type utilizing a continuously rotating flexible print wheel or disk. Normally, the type finger members are flexible in the impacting direction and more rigid in the moving direction. The rigidity in the moving direction is needed for print registration and protection during paper jams. However, some motion in the moving direction is needed at the time of impact to provide good print quality. These are two conflicting requirements. During a character printing operation the preselected type carrying finger member is impacted by the print hammer and momentarily stops because of this action. The frequency of the printing operations causes a fatigue condition to develop in the type carrier finger members with eventual breaking of the finger members from the printer disk.

SUMMARY OF THE INVENTION According to this invention the type carrying disk of the printer apparatus has a plurality of axially and laterally flexible spaced apart radial type finger members with type character elements on one face of the outermost end and adjacent the document. A plastic sleeve element is affixed to each of the radial finger members adjacent the type character element and provides a space between adjacent members to permit a limited deflection in the lateral direction on each occasion that the print hammer strikes the character element to effect a print operation.

Generally stated, it is an object of this invention to provide an improved printer.

More specifically, it is an object of the invention to provide for increasing the useful life of a flexible print disk in a printer apparatus.

Another object of the invention is to minimize the fatigue characteristics of the type carrying finger members due to stresses applied thereto during character printing operations.

Another important object of this invention is to provide sleeve elements to each of the type carrying finger members which function to provide limited deflection 0f the finger members during character printing operations.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view showing a continuously rotatable printer disk and partial platen apparatus emboding the type element deflection limiter devices of the present invention.

FIG. 2 is a partial cross-sectional view showing a type finger member with a deflection limiter device attached thereto. I

FIG. 3 is a schematic partial plan view of the rotatable type carrying disk assembly and illustrating the operation characteristics of the deflection limiter devices.

FIG. 4 is a schematic elevational view of an in-line serial printer type carrier element utilizing the deflection limiter devices of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 of the drawings, the reference number 10 denotes generally a printing head having a printer apparatus for rotatably supporting a print disk or wheel 11 and for moving it across the face of document 12, which is backed by a cylindrical print platen 13 for performing a printing operation on the document 12 in conjunction with a print hammer l4 operated by a solenoid 15 to impact type elements of the print wheel 11 against the document 12 for effecting a printing operation.

The printer type wheel assembly of the present invention forms a part of the printer apparatus of the abovereferenced cross related application. If a more detailed explanation of the printer apparatus is desired reference may be had to the cited cross reference.

The printwheel assembly comprises a resilient print disk 11 of elastic flexible material (for example, steel) and having radial slots 18 defining a plurality of radial finger members 19 with type character elements 20 attached on one face at the outermost end and adjacent the document 12. The print wheel assembly includes a hub 21 adapted to fit on a rotatable shaft 22 and be affixed thereto. The print disk assembly is designed to be continuously rotated at a relatively high velocity.. The type velocity is approximately 300 inches per second with a contact time in the order of 5 to 30 microseconds. The velocity and print pressure conditions experienced result in a momentary stopping of the preselected finger member 19 which in turn stresses that finger member in the vicinity of the hub. The frequency of the printing operations causes a fatigue condition to develop in the type carrier finger members with an eventual breaking of the fatigued finger members 19 from the printer disk 11.

The solution to this problem resides in the attachment of a plastic sleeve element 23, generally rectangular in shape, to each of the radial finger members 19 and near or adjacent to the type character end and providing a spacing between adjacent sleeve elements 23 to permit a controlled and limited deflection in the lateral or disk movement direction on each occasion that the print hammer l4 strikes the character area to effect a print operation. In other words, a predetermined air gap exists between the sleeve elements 23 attached to adjacent finger members 19. During print impact time, an amount of deflection in a lateral direction is permitted by the air gap. At contact time, the adjacent sleeve elements 23 butt up together (see FIG. 3) and the adjacent finger members 19 function to support each other. Consequently, the stresses are now controllable while printing.

In the event of a document or paper jam, a disk 11 appears as a substantially solid disk as the adjacent finger members 19 with the sleeve elements 23 attached thereto butt up to each other, thus preventing the finger members from destruction.

Referring to FIG. 4, there is shown an alternative embodiment for a print device 30 wherein the print element is a linear element having parallel slots 31 defining a plurality of parallel finger members 32 having type slugs 33 mounted at the ends thereof. In a similar manner, the plastic sleeve devices 34 are attached to the finger members 32 in the vicinity of the type slugs 33. When this type of linear print element is used in an on-the-fly printer arrangement, limited deflection is provided for the finger members 32.

From the above description and the accompanying drawings, it will be apparent that the present invention provides an improved printer disk or printer element particularly adapted for on-the-fly serial type printers. The use of deflection limiter devices greatly extends the life of the printer disk with little or no deterioration in the quality of the printing.

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

What I claim is:

1. In printing apparatus having a print carrier support movable across the front of a document and including a resilient and movable type carrying element, said type carrying element having a plurality of flexible spaced apart type finger members with type character elements on one face at the outermost end and adjacent the document, and a print hammer operable to impact a type finger of said type carrying element to drive it against the document and effect a character printing upon the document, the improvement comprising:

separate means affixed to and in fixed relation with each of the type finger members closely adjacent the type character element, said means having relatively flat side surface portions which remain in overlapping relation with the corresponding surface portions of the corresponding means of adjacent type finger members even when one of said type finger members is impacted by said print hammer to drive it against said document, and providing a predetermined spacing between the means of adjacent members less than the space between ad jacent members to permit a limited deflection in the lateral direction at the location of said means on each occasion that the print hammer strikes the character element to effect a print operation, without hindering free movement of said type finger members in a direction toward said document.

2. In printing apparatus as defined in claim 1 wherein the type carrying element is a rotatable disk having a plurality of axially and laterally flexible spaced apart radial type finger members and said means affixed to each of said radial type fingers is a plastic sleeve element.

3. In printing apparatus as defined in claim 1 wherein the type carrying element is a linearly movable member having a plurality of elongated orthogonally flexible spaced apart parallel type finger members which are flexible in directions perpendicular to the longitudinal axes of said finger members, and said means affixed to each of said finger members is a sleeve element of plastic material. 

1. In printing apparatus having a print carrier support movable across the front of a document and including a resilient and movable type carrying element, said type carrying element having a plurality of flexible spaced apart type finger members with type character elements on one face at the outermost end and adjacent the document, and a print hammer operable to impact a type finger of said type carrying element to drive it against the document and effect a character printing upon the document, the improvement comprising: separate means affixed to and in fixed relation with each of the type finger members closely adjacent the type character element, said means having relatively flat side surface portions which remain in overlapping relation with the corresponding surface portions of the corresponding means of adjacent type finger members even when one of said type finger members is impacted by said print hammer to drive it against said document, and providing a predetermined spacing between the means of adjacent members less than the space between adjacent members to permit a limited deflection in the lateral direction at the location of said means on each occasion that the print hammer strikes the character element to effect a print operation, without hindering free movement of said type finger members in a direction toward said document.
 2. In printing apparatus as defined in claim 1 wherein the type carrying element is a rotatable disk having a plurality of axially and laterally flexible spaced apart radial type finger members and said means affixed to each of said radial type fingers is a plastic sleeve element.
 3. In printing apparatus as defined in claim 1 wherein the type carrying element is a linearly movable member having a plurality of elongated orthogonally flexible spaced apart parallel type finger members which are flexible in directions perpendicular to the longitudinal axes of said finger members, and said means affixed to each of said finger members is a sleeve element of plastic material. 